There certainly exist some solutions as to how a movable standing base can be brought from a standingly stable situation on ground into a movable (rollable) situation and back again. In a plurality of solutions, it is proposed to raise the weight part so as to reach the movable (rollable) situation and to lower the weight part for reaching the standingly stable situation. This often requires long, upwardly or laterally projecting levers and force transmission devices. For an example, see EP 1 571 277 A1 (FIGS. 3a and 3b). This is disadvantageous because of the effort required, but also due to the presence of projecting parts such as levers.
Just these disadvantages, namely the necessity to raise the weight part of the standing base and thereby also to provide complicated operating elements extending to the outside of the standing base for just this lifting action, are also evident from DE 10 2014 006890 A1.
Other proposed generic bases include pumping or ratcheting devices such as described i.e. in CN 105 249 638 A1 (FIG. 3 and FIG. 5), which requires a considerable amount of operating time. Moreover, in the case of the base disclosed in CN 105 249 638 A1, it is not a priori obvious whether the base is in the stable or in the rollable state, which is unsatisfactory for safety reasons.
In US 2012/0285 497 A1 it is suggested to let the rollers be lowered and raised individually (FIG. 2, 3A, 3B), moreover, the lowering and raising of stand feet is described (FIGS. 9, 10A and 10B). The operation of each roller individually or each stand foot individually is inconvenient, confusing and requires a substantial operating effort and entails security risks. Merging the various components of the stand foot with their respective lowering and reversing mechanisms onto a single central pumping pedal causes an undesirable manufacturing cost.